BB threads – the common three are Italian (36 x 24T) and English/ British (1.37 x 24) and Raleigh not high end (1 3/8in x 26 . Less common ones are French (35 x 1), Swiss (35 x 1 but with LH threaded driveside cup) and Chater Lea (1.45in x 26).

Axle length – needs to suit chainset and to some extent the frame…

Taper dimensions JIS – most Shimano and far eastern made chainsets, ISO/Campag – most Campag and Europeanbut not older Stronglight.